Rotary drive disc brake for drawworks

ABSTRACT

A disc-type brake apparatus adapted for installation in combination with the drawworks of a well bore drilling operation for automatically sensing any reverse torque situation in the drill pipe and quickly set the brake for precluding transmission of any reverse torque to the rotary table drive and clutch mechanism therefor.

BACKGROUND OF THE INVENTION

1. Field of the Invention

This invention relates to improvements in well drilling operations andmore particularly, but not by way of limitation, to disc-brake means forprotection of the drawworks in a reverse torque situation.

2. Description of the Prior Art

In a well bore drilling operation, such as an oil and/or gas well boredrilling operation, the well bore is usually drilled into the earth bymeans of a drill bit carried at the lower end of a string of drill pipe.A rotating device known as a rotary table is normally utilized forrotation of the drill pipe during the well bore drilling operation fortransmitting rotation to the drill bit, and the power equipment utilizedfor rotating the rotary table is called a drawworks. The drawworksusually includes a countershaft interposed between a cable drum and therotary table during the drilling operation and also has a clutch memberoperable by the countershaft for controlling the driving rotation of therotary table. As the drill pipe is rotated within the well bore for thedrilling operation, a considerable torque builds up in the drill string,particularly in deep well bores, such as twenty-five thousand feet ormore in depth, which are being drilled today. When the pipe "hangs up"in the bore for any reason, the backlash or reverse torque applied tothe rotary table is exceedingly great. This reverse torque usuallycompletely "tears up" the clutch and may often do great damage to otherportions of the drawworks and well drilling equipment, in addition towhich some of the drill pipe may be lost in the well bore.

SUMMARY OF THE INVENTION

The present invention contemplates a disc-type braking attachmentadapted to be installed in the drawworks for automatically sensing anyreverse torque in the drill string and stopping the rotation of thetable drive for protection of the drawworks and rotary table from thereverse torque. The drawworks is usually provided with a countershaftconnected with the rotary table through a pulley whereby rotation istransmitted to the rotary table from the drum shaft through a suitableclutch mechanism. In one embodiment of the invention, a brake disc isconnected directly with the countershaft for rotation simultaneouslytherewith. A brake caliper assembly is mounted in the proximity of thebrake disc for selective engagement with the disc in order to stop therotation of the disc, thus stopping the rotation of the countershaft andpulley when the brake is engaged. When any reverse torque conditionarises in the drill pipe being rotated by the rotary table, a fluidsystem senses the force and immediately actuates the brake assembly forprecluding any reverse torque being transmitted through the rotary tableto the drum shaft, or to the clutch. The operator of the drillingequipment may take control of the braking apparatus subsequent to theautomatic actuation thereof and ease off the reverse torque in the drillpipe without damage to any of the drawwork equipment. The novel brakingsystem is simple and efficient in operation and economical and durablein construction.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a plan view of a drawworks and rotary table having a brakingapparatus embodying the invention installed thereon.

FIG. 2 is a side elevational view, partly in section, of a portion of acountershaft of a drawworks and having a braking apparatus embodying theinvention installed thereon.

FIG. 3 is a view taken on line 3--3 of FIG. 2.

FIG. 4 is a schematic view of a fluid actuation system utilized with abraking apparatus embodying the invention.

FIG. 5 is a view similar to FIG. 4 illustrating a modifield activationsystem of the invention.

DESCRIPTION OF THE PREFERRED EMBODIMENT

Referring to the drawings in detail, reference character 10 generallyindicates a drawworks such as normally present at the site of a wellbore drilling operation and comprising a main hoist drum 12 havinghoisting drum brakes 14 usually mounted on the opposite ends thereof. Asuitable low drum clutch 16 is normally mounted in the proximity of oneend of the drum 12 outboard of the respective brake 14, and a suitablehigh drum clutch 18 is normally mounted at the opposite end of the drum12 outboard of the other brake 14, as particularly shown in FIG. 1. Thecentral shaft 20 of the drum 12 usually extends longitudinally outwardlyfrom one end of the drum and through a suitable hydromatic 22 whichfunctions as an auxiliary brake during a well bore drilling operation,as is well known. In addition, it is usually desirable to provide asandreel 24 in the proximity of the main drum 12 and preferably insubstantial parallel relation thereto. The sandreel 24 is normallyprovided with suitable brakes 26 at the opposite ends thereof, and asandreel clutch mechanism 28 is disposed in the proximity of one of thebrakes 26. A suitable jackshaft 30 is usually provided in spacedrelation to the sandreel 24 and preferably substantially parallel withrespect thereto, and which carries a suitable low drum drive 32 operablyconnected with the main drum 12 in any well-known manner as particularlyshown in FIG. 1. An input shaft 34 is also normally provided for thedrawworks 10 and may be installed in spaced and parallel relation to thejackshaft 30. A suitable transmission chain 36 and reverse gear 38 arepreferably carried by the input shaft 34, and it is preferable toprovide a chain drive power input 40 on one end of the input shaft 34,all as is well known in the industry.

A rotary table generally indicated at 42 is normally provided in thewell bore site for rotating the drill string (not shown) during a welldrilling operation. The rotary table 42 is operably connected wth acountershaft 44 of the drawworks 10 through a rotary clutch mechanism46, normally mounted on the countershaft 44, and pulley and drive chaingenerally indicated at 48 whereby rotation is transmitted to the rotarytable for rotating the drill string.

Referring now to FIGS. 2 and 3, a disc-type brake assembly is generallyindicated at 50 which may be installed on the drawworks 10 in a mannerfor automatically sensing any reverse torque situation in the drillstring for stopping the rotation of the countershaft, thus protectingthe rotary clutch and drawworks from damage due to the reverse torque.

The brake assembly 50 as shown herein comprises a sleeve 52 having afirst outwardly extending flange member 54 provided at one end thereof.The flange 54 is provided with a plurality of suitable circumferentiallyspaced apertures 56 corresponding with the usual bolt holes 58 providedon the standard flange 60 of a hub member 62 secured to the outer end ofthe countershaft 44 in any suitable manner. A pulley 48A of the pulleyand chain assembly 48 and the flange 54 are both bolted or otherwisesecured to the outer periphery of the hub 62 by suitable bolts 64whereby the pulley 48A and sleeve 52 rotate simultaneously with thecountershaft 44.

A second outwardly extending circumferential flange member 66 isprovided on the opposite end of the sleeve 52 and is provided with aplurality of suitable circumferentially spaced bolt holes 68 whereby asuitable annular friction disc or brake disc member 70 may be secured tothe flange 66 by suitable bolts 71. Thus, the brake disc 70 will rotatesimultaneously with the countershaft 44 for a purpose as will behereinafter set forth.

A caliper brake generally indicated at 72 is mounted on a suitablesupport structure 74 provided in the proximity of the rotary clutch 46and countershaft 44 whereby the brake disc 70 passes through the caliperbrake 72 between the gripping or braking elements thereof as well knownin disc-type brake. As particularly shown in FIG. 3, it is preferable toprovide two of the caliper brakes 72 in spaced relation whereby thefriction disc 70 passes through both brakes and between the gripping orbraking elements thereof for assuring an efficient braking engagementwith the disc 70 when the brakes 72 are in an engaged position as willbe hereinafter set forth. Of course, it is preferable to provide asuitable substantially cylindrical guard or housing 76 around the outerperiphery of the disc 70 for safety purposes as is well known.

The brake assembly 50 as depicted herein is particularly designed andconstructed for installation on the countershaft 44 of the drawworks 10.However, the sleeve 52 and flanges 54 and 66 may be designed forinstallation of the braking disc 70 and caliper brakes 72 in combinationwith substantially any rotating element wherein braking action isdesired. In the particular embodiment disclosed herein, the sleeve 52and flanges 54 and 66 secure the brake disc 70 to the countershaft 44 ina manner wherein the disc is disposed outboard of the chain drives ofthe drawworks, which removes the brakes 72 from the area wherein oilfrom the chain drives might otherwise come into contact with the brakingassembly and reduce the effective braking action.

Referring now to FIG. 4, a typical arrangement for the braking system 50in association with an actuation system therefor is shown wherein asuitable driller's control valve 78, preferably a pressure regulatingair valve but not limited thereto, selectively controls the rotaryclutch 46 for a "drilling ahead" operation and the rotary braking system50 when braking action is required during the drilling operation. Thecontrol valve 78 also supplies the fluid pressure for the caliper brakeassemblies 72 for maintaining the brakes 72 in proper position to engagethe opposite sides of the brake disc 70 as will be hereinafter setforth.

An air line 80 supplies air from a suitable air supply source 82 to asuitable quick release valve 84 through a suitable rotor seal 86, andthence to the rotary clutch 46. The control valve 78 is interposed inthe air line 80 between the supply source 82 and the quick release valve84 for controlling the supply of air to and through the line 80, as iswell known. A second air line 88 supplies air to the air chamber of anair-over-oil brake actuator device 90. Of course, any suitable fluidpressure intensifier may be utilized in lieu of the air-over-oilactuator 90, if desired. In addition, it is preferable to interpose asuitable relay valve 92 upstream or ahead of the air-over-oil actuator90 for providing a quicker brake action. The caliper brakes 72 areoperably connected with the air-over-oil actuator 90 by suitable fluidlines 94 and 96. The high pressure fluid from the intensifier oractuator 90 is distributed to the brake calipers 72 through the lines 94and 96 for actuation thereof as required during a drilling operation.

The driller's control valve 78 is provided with the usual hand lever 98for normal operation thereof, as is well known, and is so arrangedwhereby one position of the valve, as, for example, the position shownin solid lines in FIG. 4 directs the control air to the rotary clutch,and another position, such as that shown in broken lines in FIG. 4directs the brakes 72. Of course, the control valve 78 also exhausts thecontrol air from the clutch when the air is being supplied to thebrakes, and vice versa, thus preventing simultaneous application of theclutch and brake.

Referring to FIG. 5, an electroc-mechanical system is shown whichillustrates a system wherein the brakes 72 continuously "sense" thetorque or "twisting force" in the drill pipe during a drillingoperation. There are many devices (not shown) presently available forcontinuously indicating the magnitude of the "twisting force" or torquebeing applied to the drill string (not shown) during a well boredrilling operation. The purpose of these devices is to prevent theseparation or "twist-off" failure of the drill pipe in the well borewhich may result in a loss of the lower portion of the drill pipe downthe well bore. when this occurs, the lost drill pipe must be recoveredfrom the well bore by a suitable fishing operation, as is well known,which is expensive and time consuming, resulting in a delay of thedrilling operation and adding to the overall cost thereof. Many devicesmay be arranged for providing a signal to a relay box 100, which isoperably connected with a suitable driller's control valve 102, similarto the valve 78 hereinbefore set forth. The signal control deviceusually merely consists in the closing of an electrical contact, evenmomentarily, for impressing a signal on the relay box 100.

The relay box 100 may be of any suitable well-known type as widely usedin the well bore drilling industry. For example, the relay box 100 asutilized in the present invention preferably contains a pair ofidentical electrical relays (not shown), a "reset" button (not shown), aterminal strip for the required electrical connections (not shown), andthree electrical cable connectors (not shown). One connector ispreferably indicated "signal", a second connector is preferablyindicated "120 Vac", and the third connector is preferably indicated"load". The signal device (not shown) hereinbefore set forth passes asignal to the relay box 100 through a suitable line 104 whereupon onerelay (not shown) of the box 100 closes a "latching" relay (not shown).The "latching" relay, in turn, supplies electrical power to the coil ofa suitable solenoid air valve 106 through a load cable 108. Powerremains on the valve 106 until the latching relay is de-energized byactuation of the normally closed "reset" button (not shown) of the relaybox 100. Activation of the "reset" button breaks the electrical circuit,removing the power from the valve 106.

The solenoid air valve 106 is preferably of a normally closed type; andwhen the valve 106 is energized, control air pressure is suppliedthrough a suitable line 110 from an air supply source 112 to a suitableshuttle valve 114. The valve 114 diverts the air pressure through a line116 to the pilot port of a normally open pilot valve 118, andsimultaneously diverts the air pressure through a line 120 to a relayvalve 122 similar to the valve 92. As hereinbefore set forth, the valve92 is an optional feature and may be eliminated, if desired. The relay122 directs the air pressure to the actuator 90 for application of thebrakes 72.

The normally open pilot valve directs air pressure to the rotary clutch46 through the quick release valve 84 and rotor seal 86. However, uponreceiving the air pressure from the shuttle valve 114, the pilot valve118 is closed, which stops or shuts off the air supply to the clutch 46and exhausts the clutch control air to provide a rapid disengagement ofthe clutch 46. Simultaneously with the exhausting of the control airfrom the clutch 46, the brakes 72 are engaged in the manner ashereinbefore set forth.

It will be readily apparent that a signal applied to the relay box 100indicating reverse torque in the drill pipe will immediately result inthe application of the brakes 72 and disengaging the clutch 46, thusprotecting the drawworks 10 from damage due to the reverse torquecondition. During normal well bore drilling operations, the drillingpersonnel will exercise control of the clutch and brake with the airvalve 78 or 102. However, when a reverse torque condition occurs in thedrill string, the system of the present invention will automaticallyoverride the driller's control, and the clutch will be exhaustedimmediately with a simultaneous actuation of the brakes.

The disc brake assembly 50 of the present invention has great torquecapacity and high heat energy dissipation capability to handle the mostdemanding braking requirements of modern day drilling operations. Ofcourse, every drawworks arrangement is somewhat different than othersuch installations, but the braking system of the invention isapplicable for installation in substantially any environment whereinrotary braking is needed.

With the system depicted in FIG. 4, the driller himself may be dependedupon for sensing any torque conditions in the drill string and mayquickly and easily activate the brakes 72 while disengaging the clutch46. With the system depicted in FIG. 5, the reverse torque conditions inthe drill string are automatically transmitted to the brake and clutchfor simultaneous activation of the brakes and disengagement of theclutch.

Subsequent to the application of the brakes 72 in a reverse torquesituation, the driller may operate the control valve 78 or 102 in theusual manner for reestablishing his own control of the well drillingoperation and may ease off on the braking pressure or the like, asrequired, and as well known in the well bore drilling industry.

From the foregoing, it will be apparent that the present inventionprovides a novel rotary braking system for application of a disc-typebraking apparatus in a reverse torque situation in drill string during awell bore drilling operation wherein the braking system is adapted forinstallation in association with the drawworks for immediately stoppingthe rotation of the main drive and clutch mechanism upon sensing of thereverse torque in the drill pipe. The novel system comprises a brakedisc operably connected with a rotary member, such as the countershaftof the drawworks, said countershaft being operably connected with theclutch mechanism. As soon as reverse torque occurs in the drill pipe,the braking apparatus engages the brake disc for stopping rotationthereof in either a forward or reverse direction, thus precluding anytransmission of the reverse torque to the clutch mechanism or othercomponents of the drawworks.

Whereas the present invention has been described in particular relationto the drawings attached hereto, it should be understood that other andfurther modifications, apart from those shown or suggested herein may bemade within the spirit and scope of this invention.

What is claimed is:
 1. In combination with a drawworks operating a drillstring during a well bore drilling operation, braking means comprisingfriction disc means connected with a rotary member of the drawworks forrotation simultaneously therewith, caliper brake means interposedbetween the drill string and rotary member and disposed in the proximityof the outer periphery of the friction elements for receiving said discmember between the braking element thereof, and means operably connectedbetween the caliper brake means and the drill string for activation ofsaid caliper brake means when reverse torque occurs in the drill stringduring the well bore drilling operation for precluding the transmissionof said reverse torque to the rotary member of the drawworks.
 2. Incombination with a drawworks operating a drill string during a well boredrilling operation, braking means as set forth in claim 1 wherein therotary member is a countershaft and the friction disc means is connectedwith the countershaft by connecting means which comprises sleeve meansdisposed in substantial axial alignment with said countershaft, firstoutwardly extending circumferential flange means provided at one end ofsaid sleeve for connection with said countershaft, and second outwardlyextending circumferential flange means provided at the opposite end ofsaid sleeve for connection with said friction disc means.
 3. Incombination with a drawworks operating a drill string during a well boredrilling operation, braking means as set forth in claim 1 wherein saidcaliper brake means comprises a pair of caliper brakes disposed inside-by-side relation in the proximity of the outer periphery of thefriction disc for simultaneously receiving the disc brake between thebraking elements thereof.
 4. In combination with a drawworks operating adrill string during a well bore drilling operation, braking means as setforth in claim 4 and including support means disposed in the proximityof the outer periphery of the friction disc for supporting said caliperbrakes thereon.